/Engine/Plugins/VirtualProduction/Takes/Source/TakeTrackRecorders/Public/TrackRecorders/MovieSceneTrackRecorder.h
This is called when the user presses StopRecording. This should be a non-blocking operation as it is called on all sources one after another as quickly as possible so they all stop at the same time. This can be important for legacy systems that still rely on floating point time.
void StopRecording()